Breastpumps are well known, and generally are comprised of breastshields (also referred to as hoods) that fit over a portion of the breast including the nipple, a vacuum pump connected to the breastshield for generating an intermittent vacuum (negative pressure) within the breastshield, and typically a receptacle for the expressed milk. In its simplest and most common form, an intermittent suction action of the vacuum pump serves to pull on the breast and massage it so as to extract milk. The expressed milk typically drains from the shield into a collection container, such as a baby bottle, which is ordinarily attached directly to the breastshield apparatus, but can also be remote (with a tubular conduit connection). For breastpumps, manually driven vacuum pumps are commonplace, as well as those that are driven by a motor (house current, battery, pneumatic, etc). The present invention is not restricted to any kind of pumping mechanism.
The vacuum pumps intermittently generate a vacuum (or sometimes a positive pressure to compress a portion) within the breastshield, with the breastshield covering the nipple and typically an adjacent amount of the breast itself. The intermittent action of the pump serves to pull on (via vacuum) and compress the breast, and thereby extract milk in an action similar to suckling. The milk so expressed ordinarily flows from the breastshield into a collection container, e.g., a bottle, for storage and later use. A breastpump of the foregoing description is shown in U.S. Pat. Nos. 4,857,051, and 4,929,229, and reference thereto may be made for further detail on breastpumps in general.
Perhaps the most commonplace breastshields typically used in conjunction with breastpumps have a conical configuration and are usually funnel-shaped. These breastshields have traditionally been made using a regular truncated partial cone portion and a nipple tunnel extension at the downstream end of the cone portion. The nipple and surrounding breast are received in the cone portion, with the nipple extending into the nipple tunnel. Under vacuum, the breast is pulled further into the breastshield, ordinarily with the nipple then being pulled further into the nipple tunnel, with the surrounding breast thereby also compressed about the nipple.
A nursing mother's nipples may thus be forced against the wall of the nipple tunnel under vacuum. This may cause friction against the wall as the nipple moves deeper into the nipple tunnel. There can also be friction between the breast and the conical portion, as well as the nipple tunnel. The rigid structure against which the mother's breast is pressed is plainly not reminiscent of the soft mouth and palate of a baby.
Inserts for use within the hood or shield of a rigid breastshield assembly are also known, and have been used for sizing the breastshield. That is, an insert would be used in a larger funnel-shaped breastshield to reduce the internal diameter of the cone portion and/or nipple tunnel, for a smaller breast. Some rigid-type breastshields have also sometimes been employed with a flexible breast-engaging portion or device mounted interior of a rigid external support or frame, not so much as a sizing mechanism but in an attempt at improved milk expression as well as comfort.